I honestly don't remember where I picked up this bit of CSS, or when, but it was quite possibly from someone here on MobileRead.
I've not done a ton of testing yet, but it seems to work at least some of the time, as long as you aren't getting carried away with how much larger you make the first letter. But I could be wrong and it might catastrophically fail
somewhere. The smarter folks here will undoubtedly tell me so and I'll learn from them!
I'm pretty sure it did
not work for Kindle AZW3, but I think it worked for KFX on Kindle, EPUB, and KEPUB on Kobo when I last played with it.
Code:
.first-letter {
font-size: 1.50em;
line-height: 0.80; /* Set line-height by using default value of 1.2 divided by font-size, above. */
vertical-align: baseline;
}